Process and apparatus for drying crucibles



L. VERGNIAUD. PROCESS-AND APPARATUS FOR DRYING CRUCIBLES.

APPLICATION FILED JULY 9| I919.

Patented Apr. 5, 1921.

18% 1f t'tarney Inventor er Ella/wet,

cruise srArss PATENT OFFICE.

LOUIS VERG-NIAUD, 0F PARIS, FRANCE, ASSIGNOR T0 CORPORATION SAID:ETABLISSE- MEETS JACOB I-IOLTZER.

PROCESS AND APPARATUS FOR DRYING CRQ'CIBLES.

Specification of Letters Patent.

Patented Apr. 5, 1921.

Application filed July 9, 1919. Serial No. 309,775.

To all w 7mm it may concern Be it known that I, LOUIS VERGNIAUD, acitizen of the French Republic, residing at 4:3 llue des Marais, Paris,have invented certain new and useful improvements in Proc esses and irpparatus for Drying crucibles, of which the following is aspecification.

Crucibles made of a clay paste or the like which are intended for use inmelting metals such as steel and other substances, that is to say, aredesigned to be exposed to a very high temperature, can be put into useonly after they have been subjected to a thorough and protracted dryingprocess.

The thoroughness of this drying is of vital importance in order to avoida cracking of the crucible which would not fail to occur on being heatedand as a result of the rapid evaporation of the moisture that is stillcontained in the paste it the latter has not been completely dried.

All drying processes, whatever their method of operation may be,consist, with a few exceptions, in drying the crucibles in a chamberwhich is maintained at a more or. less high temperature.

crucibles takes place gradually from the outside toward the inside andrequires a very long time.

The disadvantages of this method are many (a) The relatively longduration of the drying process entails, in the case of works using afairly large number of crucibles, the carrying of very large stocks thatmay at certain times, represent a considerable amount of (lead capital.

(b) The drying is irregular as regards its duration because it takesmore or less time andis more or less thorough according to the season ofthe year, the temperature and the hygrometric condition of theatmosphere of the drying chamber.

(0) The last mentioned disadvantage entails irregularities in thequality of the crucibles which occasion not uufrequently disappointments when the crucibles are in use.

The improved process of drying crucibles that forms the subject matterof the present invention enables those disadvantages to be avoided andit is characterized essentially by the feature that a systematic dryingof the crucibles is effected by causing it to take place uniformly,regularly and simultaneously from the inside and outside of the walls ofthe crucible.

A. practical constructional form of the improved apparatus for carryinginto effect the improved drying process of the present nvention, isillustrated by way of example in the accompanying drawings in which?- Fgures 1 and 2 are vertical sections taken at right angles to each otherof the improved apparatus.

F1g. 3 is a horizontal section on a larger scale of a crucible inposition upon the improved. drying apparatus.

According to the improved process the external drying of the cruciblesis effected by placing the crucibles upon heating tables 1 111 a chamberthat are constructed spec1ally for the purpose and are maintained at asuniform a temperature as possible.

The crucibles are kept upright on those tables over sets of holes 2 and3 formed therein, in an inverted position such that the rim of the mouthof each crucible rest mg upon the surface of the table circumscribes andsurrounds the whole of its set of holes and. 3 in an air-tight manner.The size and arrangement of each set of holes are such that the latterallows hot air to circulate systematically inside each crucible from itscenter to its periphery and thus efiect its internal drying.

In the example shown the central hole 2 of each set of holes 2 and 3,extends through the entire thickness of the table top 1, while the hole3 situated around the hole 2 extend only through a comparatively thinportion of the table top that is left between the top surface of thetable top 1 and a passage 4: formed in the thickness of the said tabletop.

The central hole of each set establishes communication between a"chamber 7 underneath the table top 1 and the central inner space of thecrucible being dried, whereas the holes 3 provide a communicationbetween the periphery of the inside surface of the crucible and thepassage 1- and thence air in the passages 4 communicating with the holes3 situated near the inner periphcry of each crucible, or by driving thehot air of the chamber 7 out through the hole 2 that is situated exactlyunderneath the center of each crucible.

In both cases a continuous flow of hot air is produced from the centertoward the periphery of the crucible in the downward direction along theaxis of the crucible in the list portion of its course (Fig. 1), and inthe downward direction along the sides of the crucible in the secondportion of its course (Fig. 2).

In addition to the internal flow of hot air in the crucible, the heatgiven off by the heating table top 1 insures a uniform temperature oftheair on the outside of the crucibles.

Under these circumstances the drying of the'crucibles is effectedregularly and uniformly outside as well as inside, and the length of theoperation which can be regu-. latecpl as desired, is very considerablyshortene The advantages afforded by the improved drying apparatus are(1) A great uniformity in the quality of the crucibles which may reachthe maximum. r I

(2) A very great increase in the output.

(3) A reduction in the size of the stock of crucibles required for thework of the factory,

The hereinbefore described constructional arrangements are given heresolely by way of example; the shapes, dimensions, details ofconstruction and the applications may be varied without therebydepartingfrom the nature of the invention.

Having now particularly described and ascertained the natureof my saidinven tion and in what manner the same is to be nerformed I declare thatwhat I claim is 1. A proces for drying crucibles consisting in placingthe crucibles in inverted position on a heated surface, subjecting theinterior ofthe crucibles directly to a continuouscirculation of hot air,and simultaneously subjecting the exterior surfaces of the crucibles tothe heat given off by the heated surface, whereby the crucibles aredried rapidly and systematically.

2. An apparatus for effecting an artificial drying of crucibles by theprocess claimed in claim 1, which consists ofa heating table top uponwhich the crucibles are placed in an inverted position, and which issituated over a heating chamber inclosing heating pipes; the said tabletop being provided with holes communicating with the interior of thesaid heating chamber, and being also provided with holes that arearranged around each of the aforesaid holes and are in communicationthrough a suitable pasor support inverted crucibles, said table beingprovided with a series of perforations adapted to permit heated air frombeneath the table to directly enter the interiors of the crucibles anddirectly contact with the inner surfaces of the same, a closed chamberbeneath said table, heating elements in said chamber, and means toproduce a circulation of air about the heating elements and through theperforations of the heating table 5. An apparatus for heatingcrucibles,including a heating table adapted to support inverted crucibles,saidtable being provided with perforations corresponding to the axes of saidcrucibles, a closed chamber beneath said table, heating elements in.said chamber, and a system of pipes emptying into said chamber toproduce a circulation of air about the heating elements and through theperforations of said heating table.

6. An apparatus for drying crucibles, including a heating table adaptedto support inverted crucibles, said table being provided,

with perforations corresponding to the axes of said crucibles, a closedchamber beneath said table, heating elements within said chamber, a pipesystem emptying into said chamber 'to produce a circulation of air aboutthe heating elements and through the perforations of the heating table,and means to evacuate from the crucibles the hot air and steam produced.

7. An apparatus for drying crucibles, including a heating table adaptedto support inverted crucibles and provided with perforationscorresponding to the axes of said crucibles, a closed chamber beneathsaid table, heating elements within said chamber, a pipe system emptyinginto said chamber to produce a circulation of air about the heatingelements and through the perforations of the table, said table beingalso provided with perforations arranged concentrically to the centralperforations and be low the crucibles, passages in the thickness of theheating table into which empty said concentric perforations, and meansto evacu-' ate from the heating table the air coming from the cruciblesas well as the steam evolved. a

8. An apparatus for drying crucibles, in-

eluding a heating table adapted to support inverted crucibles andprovided with periorations corresponding to the axes of said crucibles,a closed chamber beneath said table heating elements in said chamber, apipe system emptying into said chamber to produce a circulation of airabout the heating elements and through the perforations of the heatingtable, said table being also provided with perforations arrangedconcentric with the central perforations and beneath the crucibles,parallel passages in the thickness of the heating table into which emptysaid perforations, a collector arranged axially in said heating table toconnect the passages which are arranged transversely, and a passageconnecting said collector to from the crucibles as well as the steamevolved from their walls.

9. An apparatus for drying crucibles comprising a heated table providedwith a heating chamber and unobstructed perforations leading from saidchamber and opening outwardly from the top of the table, said tablebeing adapted to support a crucible in inverted position and saidcrucible being arranged over saidperforation for permitting heated airfrom the heating chamber to pass through said perforation and directlycontact with the interior wall of the crucible, and means for heatingsaid chamber.

Dated this 7th day of October, 1918.

LOUIS VERGNIAUD.

